I. Field of the Invention
The present invention is directed to systems for providing heating and cooling to the internal spaces of buildings. Specifically, the invention is concerned with systems that are energy efficient and that allow direct transfer of heat between the cooling tower, cold water supply circuit and hot water supply circuit.
II. Description of the Prior Art
In light of escalating fuel prices and limited availability of sources of energy, energy efficiency and savings in the heating and cooling of a building can be important in the operation of a building. It is a common practice to space heat and cool buildings by passing the building air over the media in the coils of the air handling equipment, such as blowers or induction units. The media in the blowers induction coils is heated or cooled water which is contained in closed circuits. In order to heat and cool a building two independent circuits must be employed, one for the cold water and the other for the hot water.
The temperature of the water in the hot water circuit is maintained by a boiler. The hot water circuit is primarily used in the winter for the heating of the perimeter areas of the building. It may also be used as a source of domestic hot water.
The interior temperature of a building during the summer is maintained by the cold water circuit. In the fall, spring and winter the cold water circuit serves to cool certain perimeter areas of the building and the interior sections of the building. The all-year cooling of the interior areas of the building is necessitated by the heat released by lights, people and equipment, etc. Continuous cooling is especially important in areas such as computer rooms.
The means of maintaining the temperature of the cold water circuit is usually referred to as the air conditioning or refrigeration system. The basic mechanical components of the system are cooling towers and a refrigeration unit or chiller. The chiller contains a condenser, a cooler or evaporator and a compressor. The cooler absorbs heat from the cold water line. It is transferred by a refrigerant to the condenser where it is further transferred to the cooling tower water. The heat is finally rejected from the system to the atmosphere through the cooling tower.
Several methods have been proposed for altering the aforedescribed conventional heating and cooling systems in order to achieve desired temperature effects while reducing the energy requirments of the system. These proposals have been limited in their success since they do not provide for comprehensive energy reduction. They are designed to reduce energy usage either during the winter or summer and they provide little savings during the spring and fall. Thus, their energy reduction capabilities are not broad enough to have a significant effect on overall energy usage.
Examples of such seasonal systems are illustrated by U.S. Pat. Nos. 3,995,443, Iverson, and 4,201,063, Martinez. These systems are only effective when the outside wet bulb temperature is below 55.degree. F. They achieve their reduction in energy usage by completely bypassing the chiller. The water from the cooling towers is filtered by a strainer and then introduced directly into the pipe lines of the cold water system. The return pipes of the cold water system also feed directly into the cooling tower. These systems realize no savings during fall, spring and summer. Also, they have no effect on the energy requirements of the heating system during the winter months.
An objective of the present invention is to provide a modification of conventional building heating and cooling systems which reduce energy input. Another objective is to provide modifications of the heating and cooling systems which produce savings throughout most of the year. A further objective is to provide a heating and cooling system which minimizes energy consumption through automatic control. A final objective is to provide for the maximum utilization of the heat available in the building and transfer it to the area needed.